This prototype of Super Uno has about 21,000 bytes different from the final version, which means that this prototype is pretty much identical to final. Virtually every single byte that is different in the prototype has the value of "FF" in the final version, meaning that the differences amount to unused space in the binary. If you compare the prototype with the final in a tile viewer, you can see that the prototype has a noisy checkerboard pattern, which is common to see in blank areas of SNES ROM images, while the final just has these areas completely blank. The only notable thing about this prototype is from the internal header, which shows that the prototype probably held a version of Mahjong Hishouden - Naki no Ryuu at some point.